SLE classification criteria item relationships: implications on SLE as a disease entity

Area of Science:

• Rheumatology
• Immunology
• Clinical Medicine

Background:

• The European Alliance of Associations for Rheumatology (EULAR)/American College for Rheumatology (ACR) classification criteria for systemic lupus erythematosus (SLE) are crucial for diagnosis and research.
• Previous analyses suggested associations between criteria domains and items were limited to within organ systems.
• This study aimed to validate and expand upon these findings in a large SLE patient cohort.

Purpose of the Study:

• To analyze potential relationships between EULAR/ACR classification criteria domains and individual criteria items in SLE patients.
• To validate previous findings of limited cross-domain associations.
• To explore the structure of SLE symptom presentation.

Main Methods:

• Cluster analysis of EULAR/ACR criteria domains in 1196 SLE patients.
• Network analysis of criteria items treated as binary variables (present/absent).
• Statistical testing for associations between items within and across domains.

Main Results:

• Cluster analysis yielded 10 clusters, but without clear patterns beyond antibody-organ relationships.
• Weak but significant associations were observed between items from different domains (r values 0.10-0.26).
• Specific correlations noted: anti-dsDNA/Sm, low complement/lupus nephritis, antiphospholipid antibodies/thrombocytopenia. Fever and serositis appeared detached in network analysis.

Conclusions:

• The EULAR/ACR SLE classification criteria domain structure shows relevance.
• However, the observed symptom associations are largely compatible with chance distribution rather than fixed SLE subsets.
• This suggests a complex and heterogeneous presentation of SLE, challenging rigid classification patterns.